Carly,

Here's a pretty good site for propagating begonias . Go down to the cane section for the ones you mentioned. Most canes root easily in a good potting soil mix but I like to add a lot of perlite to my mix so it dries faster. Tenting is not necessary if you keep it damp and the cutting is large enough and healthy. I also like to start most of mine outdoors while the weather is warm. If you start it in the house you may tent it for more humidity. You can also root it in water, but most people find that unnecessary.

The begonia you mentioned is serratipetala. It requires more care than a lot of other canes. Kartuz has it as tropical and it needs greenhouse or terrarium care. I had one once, but it is cold sensitive so I lost it in my greenhouse due to not heating during some cold nights.

Butch